How To Accurately Test For A Vitamin D Deficiency

How To Accurately Test For A Vitamin D Deficiency

The blood marker 25(OH)D does not measure the biologically active form of vitamin D, and that means it’s possible for someone to have a normal 25(OH)D level and still be biologically deficient. Parathyroid hormone, or PTH, can be used to more accurately diagnose vitamin D deficiency.

The conversion of 25(OH)D, the inactive form of vitamin D, to 1,25(OH)2D, or calcitriol, the active form, is tightly regulated by parathyroid hormone.